Conventional cytotoxic chemotherapy drugs have great toxicity to human normal cells and immune system. For example, Docetaxel and Paclitaxel are effective anti-tumor agents widely used at present. They are mainly used in various solid tumors, such as ovarian cancer and breast cancer, and have a certain efficacy against lung cancer, intestinal cancer, melanoma, head and neck cancer, lymphoma and cerebroma. Clinically, these two compounds have serious toxicity, such as arrest of bone marrow, and allergic reaction, and thus their doses have been restricted. Docetaxel exhibits bone marrow toxicity, resulting in reduction in neutrophilic granulocytes, and neurotoxicity and cardiovascular toxicity. Docetaxel can induce an allergic reaction, and a local inflammation, alopecia, hypodynamia, or even liver toxicity if it overflows the blood vessel. Mitomycin is another effective antitumor agent widely used at present. It is mainly used in various solid tumors, such as stomach cancer, colon cancer, liver cancer, pancreatic cancer, non-small cell lung cancer, breast cancer, and malignant ascitic fluid. However, clinically, mitomycin exhibits a serious toxicity and adverse reaction, its dose thus is restricted. Mitomycin can induce a bone marrow toxicity, resulting in reduction in leucocytes and platelets. It can also induce phlebitis, and tissue necrosis, alopecia, hypodynamia and hepatorenal damage if it overflows the blood vessel.

In the tumor microenvironment, the tumor cells express and secrete a great amount of asparagine endopeptidases. Expression of asparagine endopeptidase can distinguish the tumor-associated macrophage (M2 type) from the mononuclear cell and the inflammatory macrophage (M1 type). The cytokines secreted by tumor induce the mononuclear cells to transform to tumor-associated macrophages. The tumor-associated macrophages can stimulate and produce strong immunosuppression and directly help infiltration and metastasis of tumor cells. Meanwhile, a great amount of proteolytic enzymes are produced during metastasis of tumor cells to degrade intercellular matrix. Thus, new compounds can be chemically synthesized and screened based on biochemistry and pharmacological detection and screening to find a chemical conjugate that is able to be activated by asparagine endopeptidase and conjugated to drug via a secondary activated linker. The conjugate can link different groups for solubility or modification as needed to drugs for chemotherapy having specific cytotoxicity, thus producing new drugs having new functions, such as new targeting, activation, stability, solubility, metabolism, toxicity and efficacy, etc.